JP2006070263A - Method for preparing powdery (poly) urea - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide micronized (poly) urea for use as a thickening agent in a lubricant. <P>SOLUTION: (Poly) urea is formed by reacting at least 1 type of polyisocyanate with at least one type of polyamine and if necessary at least one type of monoamine in at least 1 type of solvent in a reactor. The method for preparing (poly) urea powder comprises drying under exposure to shearing force the thus formed (poly) urea in the above reactor and thus forming (poly) urea powder. Preferably, the total weight percentage of polyisocyanate and polyamine to the total weight of the solvent ranges from 10% to 50%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides a method for preparing a (poly) urea powder, a composition containing the (poly) urea powder obtained by the method, and a thickener, in particular, in that method for a lubricant such as a so-called polyurea grease. The use of the resulting polyurea particles.

  According to the prior art, so-called polyurea greases containing polyurea as a thickener in base oils are still mostly prepared by the so-called “in situ” method. In the “in situ” process, polyurea thickeners are produced “in situ” by polyaddition of polyisocyanates dissolved in a solvent or mineral oil, and also polyamines dissolved in mineral oil or solvent. The polyurea obtained by this procedure exists in a divided, pre-swelled form, and after removal of the solvent, forms a gel-like structured paste in the base oil (mineral oil) and further homogenizes to form a homogeneous grease. Form. This method has the disadvantage that the product obtained contains impurities from the reaction. TDI is particularly important here. Therefore, special authorization procedures are required to implement the “in situ” method. A further disadvantage is the presence of control problems due to high viscosity in the “in situ” process. Heterogenization may occur within the reaction assembly. Further, since the polyaddition reaction proceeds exothermically, a problem of heat removal may occur. This so-called “in situ” prior art is described in detail in EP 0534248 A1 and is referred to here.

  The method of EP 0534248A1 attempts to solve the disadvantages of the prior art described above, in which polyaddition to give polyurea is first carried out by extrusion by solvent (especially toluene, butanol, ethyl acetate, chloroform, etc.). ) Or without solvent. The resulting solid is subsequently reworked, ie dried (suction filtration or evaporation or stripping removal of the solvent), then ground and finally processed into grease. In the process described in EP 0534248A1, polyurea is first prepared by reaction of polyisocyanate with an amine. When the components have fully reacted, these products are then ground in a dry state to a powder and the coarsely ground product into a paste in base oil, under a pressure above 500 bar (0.05 MPa). Processed into “PU grease” with a high-pressure homogenizer. The disadvantage of this method is that the powder obtained by grinding is relatively coarse particles. This is a drawback when the polyurea powder is charged into the base solution. The use of a high pressure homogenizer is therefore essential in this method. This method thus requires a high energy input. The process of EP 0534248 A1 has the further disadvantage that several reactors and several process steps are required. EP 0534248 A1 further requires very large amounts of solvent which must be distilled again after the reaction. A large amount of solvent is necessary, for example, so that the reaction product formed can be transported to a suction filter for drying. This all results in relatively high energy consumption and relatively high solvent circulation costs. The solventless process by extrusion has the disadvantage that it may cause problems (especially cracks) in removing heat. Both require subsequent grinding of the dried reaction product, which also requires very high costs.

  Similarly, the method of WO 02/04579, which is said to provide a polyurea grease having low noise properties, is a process of preparing polyurea first, then the particle size of thickener particles during charging into the base oil. Requires a shearing process in which is reduced to less than 500 μm. Preferably, the particle size is reduced by a shearing method to a range where all particles are less than 100 μm and 95% of the particles are less than 50 μm. However, still further preparation of micronized polyurea suspensions is not possible with an acceptable energy input by the method described therein. WO 02/04579 does not describe a non-fine dry polyurea powder that can be put into a base oil by a user in situ, for example.

  Furthermore, WO 02/02683 discloses a rubber composition comprising a fine polyurea filler. The polyurea filler particles used here have a particle size determined by an optical microscope of 0.001 to 500 μm. However, the polyurea particles are not isolated and are preferably prepared in the presence of rubber. The dried fine polyurea powder, its preparation method and its use as a thickener in so-called PU greases are not mentioned.

  The inventor has surprisingly surprisingly prepared particularly finely divided (poly) urea powders by the use of a polyurea preparation process in a reactor that simultaneously removes volatile contents while applying shear. Succeeded. This method allows the preparation of finely divided dry (poly) urea powders in a single reactor without further grinding steps. The resulting (poly) urea particles are sufficiently finely divided and can be introduced into the base oil for the preparation of (poly) urea grease without increasing energy consumption. The use of more finely divided particles allows the use of low pressures during homogenization, especially in the case of charging into the base oil for the preparation of so-called PU greases, which means that energy and material Bring savings.

  The present invention thus reacts at least one isocyanate with at least one amine in at least one solvent in the reactor and dries the (poly) urea formed in the reactor under shear force exposure. A (poly) urea powder, thereby forming a (poly) urea powder.

  According to the present invention, (poly) urea includes monourea compounds and polyurea compounds. Monourea compounds in the molecule

基（ここで、自由原子価は、少なくとも１種の有機基で飽和され、尿素自身はしたがって除外される）を含むものである。然しながら、本発明によれば、分子において少なくとも２個の

Radicals, where the free valence is saturated with at least one organic group, and urea itself is therefore excluded. However, according to the present invention, at least two molecules in the molecule

基を含むポリ尿素化合物が好ましい。

Polyurea compounds containing groups are preferred.

  The present invention preferably reacts at least one polyisocyanate with at least one polyamine and optionally at least one monoamine, and the formed polyurea is dried in the reactor under shear force exposure. The present invention relates to a method for preparing a polyurea powder, characterized by forming a polyurea powder.

  Preferably, the weight ratio of the total weight of polyisocyanate and monoamine and polyamine to the total weight of solvent is from 10% to 50%. This ratio is particularly preferably 15% to 35%. A ratio above 50% is disadvantageous because thickening of the suspension during the reaction gradually hinders the dispersion and reaction of the reaction partner. A ratio of less than 10% is disadvantageous because the yield is uneconomical.

  The solvent used in the suspension used according to the invention is preferably selected from organic solvents. The solvent is particularly preferably an optionally substituted linear, branched or cycloaliphatic or aromatic hydrocarbon such as butane, pentane, n-hexane, cyclohexane, n-octane, isooctane, petroleum ether, benzene, toluene, It is selected from organic solvents selected from the group consisting of halogenated hydrocarbons such as xylene, methylene chloride and chlorobenzene, ethers such as diethyl ether and tetrahydrofuran, ketones such as acetone, and esters such as ethyl acetate and butyl acetate.

  n-Hexane, n-heptane, petroleum ether and ethyl acetate are particularly preferred solvents.

  Particularly preferred solvents for food applications are those listed in “Federal Regulatory Standards” CFR 21 §§170-199 of the US statute, for example, isoparaffinic petroleum ethers according to §173.280, §173.270 Hexane according to § 173.210, ethyl acetate according to § 173.228 and 1,3-butyl glycol according to § 172.712.

  It is also possible to use a mixture of one or more solvents.

  The preparation of polyurea can be carried out in a manner known per se by reaction of at least one polyisocyanate with at least one polyamine in a suitable solvent.

  The preparation of polyurea involves the precipitation of polyurea in a solvent such as those listed above at a temperature of −100 ° C. to 250 ° C., preferably 20 ° C. to 80 ° C., and at least one polyisocyanate and at least 1 The reaction is suitably carried out by reaction with a seed monoamine or polyamine.

  The polyurea obtained preferably has a melting point or decomposition point of ≧ 180 ° C., preferably ≧ 200 ° C., particularly preferably ≧ 240 ° C. Their glass transition temperatures, if present, are above 50 ° C, preferably above 100 ° C.

  Suitable polyisocyanates for the preparation of polyureas are, for example, hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), 2,2′-, 2,4′- and 4,4′-diisocyanatodiphenylmethane (MDI). , Polymethylene polyphenyl isocyanate (PMDI), naphthalene diisocyanate (NDI), 1,6-diisocyanato-2,2,4-trimethylhexane, isophorone diisocyanate (3-isocyanatomethyl) -3,5,5-trimethylcyclohexyl isocyanate , IPDI), tris (4-isocyanatophenyl) -methane, phosphoric acid tris- (4-isocyanatophenyl ester), thiophosphoric acid tris- (4-isocyanatophenyl ester) and the aforementioned low molecular weight diisocyanate Oligomerization products obtained by the reaction of diols or polyalcohols, in particular ethylene glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane and pentaerythritol, with free isocyanate groups Products with residual content, and further low molecular weight diisocyanates as described above and hydroxyl group-containing polyesters, for example polyesters based on adipic acid and butanediol and hexanediol having a molecular weight of 400 to 3,000, etc. Or by reaction with hydroxyl group-containing polyethers such as polyethylene glycol, polypropylene glycol and polytetrahydrofuran having a molecular weight of 150-3,000. Oligomerized products having a residual content of free isocyanate groups, and also oligomerized products obtained by reaction of the aforementioned low molecular weight diisocyanates with water or by dimerization or trimerization Products such as dimerized toluene diisocyanate (Desmodur TT) and trimerized toluene diisocyanate, and isocyanate groups, for example isocyanate groups based on isophorone diisocyanate, having a residual content of free isocyanate groups It is a polyuretodione. The preferred content of free isocyanate groups in the polyisocyanate is 2.5% to 50% by weight, preferably 10% to 50% by weight, particularly preferably 15% to 50% by weight. Such polyisocyanates are known and can be obtained as commercial products. In this regard, Houben-Weyl, Methoden der Organischen Chemie, volume XIV, pp. 56-98, Georg Thieme Verlag Stuttgart 1963, Encyclopedia of Chem. Technol. , John Wiley 1984, vol. 13, p. 789-818, Ullmann's Encyclopedia of Industrial Chemistry, VCH, Weinheim, 1989, vol. See A 14, pages 611-625, and the products of the Death Module and Crelan series (Bayer).

  Blocked polyisocyanates that can react with polyamines under the reaction conditions described above are also suitable polyisocyanates. These include all the polyisocyanates already mentioned, in which case the isocyanate groups can be separated and are blocked with suitable groups that separate again at elevated temperatures to liberate isocyanate groups. Suitable groups which can be separated are in particular caprolactam, malonic esters, phenols and alkylphenols such as, for example, nonylphenol, and imidazole and sodium bisulfite. Particular preference is given to polyisocyanates blocked with caprolactam, malonic esters and alkylphenols, in particular polyisocyanates based on toluene diisocyanate or trimerized toluene diisocyanate. The preferable content of the blocked isocyanate group is 2.5% to 30%. Such blocked polyisocyanates are known and are commercially available. In this regard, reference is made to the products of Houben-Weyl, Methoden der Organischen Chemie, volume XIV, pages 56-98, Georg Thieme Verlag Stuttgart 1963, and the Death Module and Clerant series (Bayer).

  Preferred polyisocyanates are hexamethylene diisocyanate (HDI), toluene-diisocyanate (TDI), 2,4′- and 4,4′-diisocyanatodiphenylmethane (MDI), polymethylene polyphenyl isocyanate (PMDI), 1,6 Reaction of diisocyanato-2,2,4-trimethylhexane, isophorone diisocyanate (IPDI) and the aforementioned low molecular weight diisocyanates with water or diols or polyalcohols, in particular ethylene glycol, 1,4-butanediol, 1,6- Oligomerized products obtained by reaction with hexanediol, trimethylolpropane and pentaerythritol, which have a residual content of free isocyanate groups, as well as by dimerization or trimerization 2.5% to 50% by weight of the resulting oligomerization product, including dimerized toluene diisocyanate (Desmodur TT) and trimerized toluene diisocyanate, and isocyanate groups such as isocyanate groups based on isophorone diisocyanate %, Preferably 10 to 50% by weight, particularly preferably 15 to 35% by weight, of aliphatic polyuretdiones having a free isocyanate group content. 2,4'- and 4,4'-diisocyanatodiphenylmethane (MDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI) and polymethylene polyphenyl isocyanate (PMDI) are highly preferred.

  Suitable polyamines are aliphatic di and polyamines such as hydrazine, ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1-amino-3-methylaminopropane, 1,4-diaminobutane, N, N′-dimethyl-1-ethylenediamine, 1,6-diaminohexane, 1,12-diaminododecane, 2,5-diamino-2,5-dimethylhexane, trimethyl-1,6-hexanediamine, diethylenetriamine, N , N ′, N ″ -trimethyldiethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine having a molecular weight of 250 to 10,000, dipropylenetriamine, tripropylenetetramine, bis- (3-aminopropyl) A) , Bis- (3-aminopropyl) -methylamine, piperazine, 1,4-diaminocyclohexane, isophoronediamine, N-cyclohexyl-1,3-propanediamine, bis- (4-aminocyclohexyl) methane, bis- ( 4-amino-3-methylcyclohexyl) -methane, bisaminomethyltricyclodecane (TCD-diamine), o-, m- and p-phenylenediamine, 1,2-diamino-3-methylbenzene, 1,3- Diamino-4-methylbenzene (2,4-diaminotoluene), 1,3-bisaminomethyl-4,6-dimethylbenzene, 2,4- and 2,6-diamino-3,5-diethyltoluene, 1, 4- and 1,6-diaminonaphthalene, 1.8- and 2,7-diaminonaphthalene, bis- (4-amino Phenyl) -methane, polymethylene polyphenylamine, 2,2-bis- (4-aminophenyl) -propane, 4,4′-oxybisaniline, 1,4-butanediol bis- (3-aminopropyl ether) , Polyamines containing a hydroxyl group such as 2- (2-aminoethylamino) ethanol, polyamines containing a carboxyl group such as 2,6-diaminohexanoic acid, and further containing an amino group, preferably 500 to 10,000 Liquid polybutadiene or acrylonitrile / butadiene copolymer having an average molecular weight of and containing amino groups, for example based on polyethylene oxide, polypropylene oxide or polytetrahydrofuran, 0.25 to about 8 mmol / g, preferably 1-8 mmol / g First grade or second grade Polyether having an amino group content. Such polyethers containing amino groups are commercially available (eg, Jeffamine D-400, D-2000, DU-700, commercially available from Texaco Chem. Co., ED-600, T-403 and T-3000).

  Particularly preferred polyamines are hydrazine, ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1-amino-3-methylaminopropane, 1,4-diaminobutane, N, N′-dimethylethylenediamine, 1, 6-diaminohexane, diethylenetriamine, N, N ′, N ″ -trimethyldiethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine having a molecular weight of 250 to 10,000, dipropylenetriamine, tripropylenetetramine , Isophorone diamine, 2,4-diaminotoluene and 2,6-diaminotoluene, bis- (4-aminophenyl) -methane, polymethylene polyphenylamine and amino groups, preferably Liquid polybutadiene or acrylonitrile / butadiene copolymer having an average molecular weight of 00 to 10,000 and containing amino groups, for example based on polyethylene oxide or polypropylene oxide, 1 to 8 mmol / g primary or secondary amino groups A polyether having a content of

  Highly preferred polyamines are ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine having a molecular weight of 250 to 10,000, 2, 4-diaminotoluene and 2,6-diaminotoluene, bis- (4-aminophenyl) -methane and polymethylene polyphenylamine and containing amino groups, for example based on polyethylene oxide or polypropylene oxide, 1-8 mmol / A polyether having a primary or secondary amino group content of g and a molecular weight of 250 to 2,000.

  In addition to polyamines, further compounds that are reactive towards polyisocyanates can also be added, in particular monoamines such as ammonia, C1-C18-alkylamines and di- (C1-C18-alkyl) -amines, etc. And arylamines such as aniline, C1-C12-alkylarylamines, and the like, and aliphatic, cycloaliphatic or aromatic mono-, di- or poly-C1-C18-alcohols, aliphatic, cycloaliphatic or aromatic Containing mono-, di- or poly-C1-C18-carboxylic acids, aminosilanes, such as 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane, and the like, and preferably carboxyl, epoxide or hydroxyl groups, Has an average molecular weight of 500 to 10,000 Liquid polybutadiene or acrylonitrile / butadiene copolymers and chain terminators such as polyethers and polyesters having hydroxyl and / or carboxyl groups that have a molecular weight of 200 to 10,000 and are reactive towards polyisocyanates be able to. Examples of these monoamines that are additionally used are ammonia, methylamine, dimethylamine, dodecylamine, octadecylamine, oleylamine, stearylamine, ethanolamine, diethanolamine, β-alanine or aminocaproic acid. The amount of these additional amines, alcohols, carboxylic acids and polyethers and polyesters containing hydroxyl and / or carboxyl groups depends on their content of groups which are reactive towards polyisocyanates and are 0 per isocyanate equivalent. ~ 0.5 mol of reactive groups.

  As already described, the polyurea particles of the present invention are prepared at least at least one polyisocyanate and at least one polyisocyanate with precipitation of polyurea in a solvent at a temperature of −100 ° C. to 250 ° C., preferably 20 ° C. to 80 ° C. It can be prepared by reaction with one monoamine or polyamine. Preferred solvents are in particular organic, preferably aprotic solvents that are not reactive with isocyanates, in particular optionally substituted linear, branched or cyclic aliphatic or aromatic hydrocarbons such as butane, Pentane, n-hexane, petroleum ether, cyclohexane, n-octane, isooctane, benzene, toluene, xylene and the like, halogenated hydrocarbons such as methylene chloride and chlorobenzene, ethers such as diethyl ether and tetrahydrofuran, ketones such as Ester such as acetone, ethyl acetate and butyl acetate.

  Particularly preferred solvents for food applications are isoparaffinic petroleum ether, hexane, acetone, ethyl acetate and 1,3-butyl glycol, as already mentioned above.

  Monourea compounds are prepared by reaction of monofunctional isocyanates with monofunctional amines, in particular in processes corresponding to polyurea compounds. For convenience, these are compounds having a thickening action in the base oil, like polyurea.

  In contrast to the so-called “in situ” prior art described above, according to the present invention, the preparation of (poly) urea particles is not carried out in a so-called lubricant base oil as follows. The solvents used for the preparation of polyurea and present in the suspension to be spray-dried differ from so-called base oils, in particular by their viscosity and their molecular weight. The viscosity of the solvent is up to about 1 cSt (40 ° C.), but for base oils it is at least about 4, preferably at least about 5 cSt (40 ° C.). The base oil has a molecular weight distribution due to its preparation method, purification / distillation. Conversely, the solvent has a fixed molecular weight.

  The reaction of the polyisocyanate with the monoamine or polyamine is preferably performed by first charging the polyisocyanate into the solvent and then mixing the polyamine in the solvent or first charging the monoamine and polyamine into the solvent and mixing the polyisocyanate. Done. The amount of polyisocyanate and monoamine or polyamine depends on the desired properties of the polyurea particles. By using an excess of monoamine or polyamine, these particles contain, for example, still-bonded amino groups, or if an excess of polyisocyanate is used, they are bonded (still-bonded). ) Containing isocyanate groups.

  A preferred quantitative ratio of polyisocyanate to polyamine is 0.5 to 2.0, more preferably 0.7 to 1.3, especially 0.8 to 1.2 mol of isocyanate groups per mole of amino groups.

  If a monoamine such as stearylamine is used as a chain terminator, this thus affects the ratio of polyamine to polyisocyanate.

  In addition to monoamines or polyamines, further multifunctional compounds that are reactive towards isocyanates, such as in particular polyols, can be used in the present invention, resulting in the formation of polyurea-urethanes. Such polyols can also contain polyether groups. The polyol can be, for example, the aforementioned polyalcohol used for the preparation of the polyisocyanate oligomer.

  As already mentioned above, emulsifiers and dispersants can be added before or during the preparation process in order to adjust the particle size of the polyurea.

  According to the invention, the polyurea has the formula:

の少なくとも２つの繰り返し尿素単位を含むものである。

In which at least two repeating urea units are included.

  According to the invention, polyureas containing on average 2, 3 or 4 such urea groups are particularly preferred.

  The polyurea particles preferably comprise a polyurea having a weight average molecular weight determined by gel permeation chromatography on polystyrene as a standard, between 500 and 20,000.

  Particularly preferred polyureas are 2,4′- and 4,4′-diisocyanatodiphenylmethane (MDI), hexamethylene-diisocyanate (HDI), toluene-diisocyanate (TDI) and polymethylene polyphenylisocyanate (PMDI); Ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 2,4-, 1,6-diaminohexane, diaminotoluene and 2,6-diaminotoluene, bis- (4-amino-phenyl) -methane and Polymethylene polyphenylamines and / or monoamines such as ammonia, C1-C18-alkylamines and di- (C1-C18-alkyl) -amines, and arylamines such as aniline and C1-C12-alkyls Aryl Reaction products of amine as well as polyurea having a molecular weight of 500 to 3,000.

  When the reaction to give the (poly) urea is complete, the (poly) urea powder is dried by removing the solvent and any residual volatile components that may be present from the reactor. Preferably, drying is performed at a temperature in the range of 40 ° C to 80 ° C. In a preferred variant, it is preferably dried under a reduced pressure of less than 300 mbar (0.03 MPa). Particularly preferably, drying is performed under a pressure in the range of 10 to 180 mbar (0.001 to 0.018 MPa).

  The method according to the invention is characterized in that at least the drying step is carried out with a shearing force applied. By applying a shear force, it is meant that a shear force is applied to the (poly) urea particles in the reactor. The state of applying a shear force is preferably already applied during the reaction between the polyisocyanate and the polyamine, so that the formation of large particles or aggregates is avoided from the beginning.

The shear force applied in the reactor is preferably 1 to 10 ⁴ / sec.

  The method of applying the shearing force during drying and, in some cases, during the reaction is appropriately selected so that the particle size range described below is achieved for the resulting (poly) urea powder.

  As a suitable reactor in which the preparation and drying of (poly) urea powder can be performed in a state where shearing force is applied, a horizontal uniaxial mixer is preferably used.

  The dry polyurea powder obtained by the process according to the invention is preferably less than 5% by weight, more preferably less than 3% by weight, still more preferably less than 1% by weight of volatile components (those having a boiling point of less than 250 ° C. ) Residual content. The dry (poly) urea powder obtained by the process according to the invention preferably has an average particle size of less than 150 μm, preferably less than 100 μm, and even more preferably less than 80 μm. The lower limit of the average particle size is preferably greater than about 20 μm. A particle size exceeding 150 μm is not preferable because it makes it difficult to uniformly introduce (poly) urea particles into the base oil. An average particle size of less than 20 μm is undesirable because it increases the cost of shearing, while the finely divided powder more easily forms dust.

  The average particle diameter here means the weight average of the particle diameter, and is determined by coherent light scattering (laser method). This method gives an average particle size including aggregates. The size of the primary particles is remarkably small, for example about 1-10 μm. Substantial deagglomeration of the polyurea particles prepared according to the present invention can be achieved by the use of a high pressure homogenizer for the PU grease prepared according to the present invention.

  Preferably, more than 90% of the particles of the (poly) urea powder obtained have a particle size of less than 100 μm.

  The invention further provides a dry (poly) urea powder obtainable by the process according to the invention, in particular an average particle diameter of 20 to 150 μm, preferably 20 to 100 μm, and preferably less than 0.5% by weight, more preferably Relates to dry (poly) urea powders having a solvent content of less than 0.3% by weight, still more preferably less than 0.2% by weight.

  The advantages of dry (poly) urea powders prepared according to the invention are notably the first time for users to use “in situ” methods, which are problematic from the point of view of work safety, or over 500 bar. It has been found that it is possible to prepare so-called PU greases without using high-pressure homogenization under high pressure. Thus, the (poly) urea particles obtainable by the method according to the invention open up a field of applications or a population of users where the use of (poly) urea has not previously been considered due to the above-mentioned drawbacks It is expected.

The (poly) urea powders obtainable by the process according to the invention are in particular those having a high specific surface area. Such a high specific surface area cannot be obtained by other conventional drying methods of the prior art and subsequent grinding. The (poly) urea powder according to the invention has a specific surface area of 15 to 50 m ² / g, preferably 35 to 45 m ² / g (measured by mercury intrusion method).

  The invention further relates to a process for the preparation of a composition comprising the above-mentioned (poly) urea powder suspended in at least one base oil.

  In this case, the base oil basically comprises any preferred organic liquid that is inert to the (poly) urea powder. In particular, they are liquids that can be thickened by (poly) urea powders.

  Preferred base oils are, for example, ordinary base oils used in lubricants, such as ordinary mineral oils, synthetic hydrocarbon oils used or synthetic or natural ester oils or mixtures thereof. In general, typical applications require viscosities in the range of about 10 to about 200 cSt at 40 ° C., but these have viscosities in the range of about 4, preferably 5 to about 400 cSt at 40 ° C. Mineral oils that can be used according to the invention can be conventional refined base oils derived from paraffinic, naphthenic or mixed crude oils. Synthetic base oils include ester oils such as glycol esters, C13 oxo acid diesters of tetraethylene glycol, or complex esters such as 1 mole of sebacic acid and 2 moles of tetraethylene glycol and 2 moles of 2- Examples include those formed from ethylhexanoic acid.

  Natural ester oils include saturated and unsaturated natural ester oils, such as vegetable or animal oils and fats (which are known triglycerides of naturally occurring fatty acids), and their hydrogenated products or esters An exchange reaction product may be mentioned. Preferred such natural ester oils are those derived from plants, in particular vegetable oils substantially comprising mixed glycerol esters of higher fatty acids having an even number of carbon atoms, such as apricot oil, avocado oil, cottonseed oil, borage oil, thistle oil , Peanut oil, hydrogenated peanut oil, cereal embryo oil, cannabis oil, hazelnut oil, pumpkin seed oil, coconut oil, linseed oil, bay oil, poppy oil, macadamia oil, corn oil, almond oil, evening primrose oil, olive oil Hydrogenated palm oil, palm oil, pistachio seed oil, rapeseed oil, castor oil, sage oil, sesame oil, soybean oil, sunflower seed oil, grape seed oil, walnut oil, wheat germ seed oil, wild Rose oil, coconut fat, palm fat, palm seed fat or colza oil. Sunflower seed oil, soybean oil and rapeseed oil are preferred.

  Other synthetic oils include synthetic hydrocarbons such as poly-α-olefins, alkyl benzenes such as alkylate bottom products from alkylation of benzene and tetrapropylene, or copolymers of ethylene and propylene, silicones Oils such as ethylphenylpolysiloxane, methylpolysiloxane, etc., polyglycol oils such as those obtained by condensation of butyl alcohol and propylene oxide, carbonates such as C8 oxo alcohols and carbonates to form half esters Examples thereof include a product of a reaction with ethyl and a subsequent reaction with tetraethylene glycol. Other suitable synthetic oils include polyphenyl ethers, such as those containing about 3-7 ether linkages and about 4-8 phenyl groups. Further base oils include perfluorinated polyalkyl ethers as described in WO 97/477710.

  The base oil preferably has a boiling point above 100 ° C, more preferably above 150 ° C and even more preferably above 180 ° C.

  Preferred base oils are conventional refined mineral oils derived from paraffinic, naphthenic or mixed crude oils, synthetic hydrocarbons such as poly-α-olefins and alkylbenzenes and ester oils.

  Particularly preferred base oils for food applications are those base oils listed in US statutory “Federal Regulatory Standards” CFR 21 §§ 170-199, such as white oil according to § 172.878, § 178.3530 Isoparaffinic hydrocarbons according to, mineral oils according to § 178.3620, polyethylene glycols according to § 178.3750 and fatty acid methyl / ethyl esters according to § 172.225.

  Preferably, the composition prepared according to the invention comprises 2% to 25% by weight, preferably 5% to 15% by weight (poly) urea according to the invention, based on the total amount of base oil.

  The preparation method of the composition suitably includes a suspension of (poly) urea powder prepared according to the invention in at least one base oil. Suspension of (poly) urea powder in base oil is known per se for methods known per se, for example for the preparation of homogenizers or roll mills or high-speed dissolvers and such dispersions Further apparatus can be performed, for example, by corundum disks, colloid mills, pinned disk mills and the like. The introduction of the powder is carried out by first preparing a paste at a temperature of about 100 ° C. to 220 ° C., preferably about 120 ° C. to 200 ° C., and then homogenizing the mixture once to several times in the apparatus described above. . In particular, in some cases at temperatures up to about 200 ° C., subsequent cooling and several (two or more) homogenizations proved particularly favorable. As mentioned above, if necessary, the (poly) urea particles obtained according to the invention can be further deagglomerated during the preparation of the PU grease, either alone or additionally using a high-pressure homogenizer, for example a so-called APV homogenizer, Thereby, the average particle size can be further reduced to the primary particle size range.

  By using a particularly finely divided (poly) urea powder according to the invention with a high specific surface area, the input of polyurea powder requires substantially less energy than the input of (poly) urea powder prepared by grinding. . In addition, a smaller amount of polyurea powder is required to achieve the same viscosity.

  The invention further relates to the use of (poly) urea powders prepared according to the invention as thickeners. The (poly) urea powders according to the invention can be used as thickeners, for example in the following uses: paints, lacquers, adhesives, pastes, greases, solutions, food applications or food compositions and the like.

  The (poly) urea powders prepared according to the invention are particularly preferably used as thickeners in lubricants.

  In this case, the polyurea powder prepared according to the invention is preferably used in an amount of about 5% to 25% by weight, based on the total amount of base oil.

  The invention further relates to a lubricant comprising a polyurea powder prepared according to the invention, at least one base oil and optionally further usual auxiliary substances and additives for lubricants. These normal auxiliary substances and additives include, for example, corrosion inhibitors, high pressure additives, oxidation resistance agents, friction modifiers and wear protection additives.

  Additives used in lubricating greases are described, for example, in Boner, “Modern Lubricating Greens”, 1976, Chapter 5.

  In a particular embodiment, the invention is used as a composition, in particular as a lubricant, comprising at least one (poly) urea powder according to the invention, at least one base oil and at least one further thickener. The present invention relates to a composition for Typical additional thickeners used in lubricating grease compositions include, among others, alkali metal soaps, clays, polymers, asbestos, carbon black, silica gel and aluminum composites.

  So-called soap greases are preferred according to the invention. These are in particular metal salts, in particular monobasic, optionally substituted, preferably higher (> C8) carboxylic acid metal salts, it is also possible to use mixtures of carboxylic acid metal salts. is there. These include, in particular, metal salts of carboxylic acids with alkali metals and alkaline earth metals such as sodium, potassium, lithium, calcium, magnesium, barium or strontium, and other metals such as aluminum and zinc. It is a metal salt. Lithium and calcium soaps are most widely used. Simple soap-lubricating greases are alkali metal salts of long chain fatty acids (at least C8) (often used are 12-hydroxystearic acid, lithium 12-hydroxystearate formed from lithium hydroxide monohydrate) and mineral oils Formed from. Complex soap oils are also widely used, including metal salts of mixtures of organic acids. A typical composite soap lubricating grease used today is a composite lithium soap lubricating grease prepared from 12-hydroxystearic acid, lithium hydroxide monohydrate, azelaic acid and mineral oil. Lithium soaps are described in a number of patents, including US Pat. No. 3,758,407, US Pat. No. 3,793,1973, US Pat. No. 3,929,651 and US Pat. No. 4,392,967, and examples are given.

  According to the present invention, the weight ratio between the weight of soap grease and the weight of polyurea can be from 100: 1 to 1: 100. The attraction of the (poly) urea powders prepared according to the invention in a mixture with soap greases is in this case isolated dry polyurea, in particular in contrast to PU greases prepared via an in situ method. The powder can be introduced into the soap grease composition and its properties can be influenced there in a controlled manner. Experiments have shown that mixing 2% polyurea grease with lithium soap grease surprisingly improves the reduction of penetration and, therefore, the consistency of the grease. Furthermore, the dropping point is increased compared to pure lithium soap grease.

  The invention is illustrated by the following examples.

Polyurea 1:
128.43 g of methylene-4,4′-diphenyl diisocyanate having an NCO content of 32.68% is stirred with constant stirring with 44.58 g of diethyltolylenediamine and 99 in 1,350 g of petroleum ether. Add to a mixture with 3 g coconut fatty amine.

  After completion of the reaction, the solvent of the formed suspension is removed from the reaction under exposure to shear and the formed powder is dried under applied vacuum.

  A 15% suspension of the resulting powder in naphthenic base mineral oil is stirred at about 150 ° C. for 1 hour, cooled, and then homogenized three times on a three-stage roll mill. The dropping point and consistency of the resulting grease is determined. Grease made from the same composition of polyurea powder and the same base oil is used as a comparison. The powder based on the control grease was prepared in a kneading extruder and then ground in the usual way.

result:
Dropping point Penetration after use
[DIN 51580] P _u P _{w, 60} P _{w, 60,000}
Polyurea grease, 212 ° C 204 200 204
Reactor (invention)
Control grease, 210 ° C. 242 242 259
Kneading extruder

  The consistency of the grease is determined by measuring the cone penetration according to ISO 2137 for the grease sample. The penetration of the cone here corresponds to the depth of penetration of the cylindrical cone into the grease sample after 5 seconds, measured in 1/10 mm, the higher the value, the greater the penetration depth. , Grease consistency is low. A comparison is made between the unused penetration Pu and the penetration Pw, 60 or Pw, 60,000 after use. Unused penetration is measured for untreated grease. Penetration after use is measured after the sample has been used in 60 use operations (Pw, 60) or 60,000 use operations (Pw, 60,000). The difference between the penetrations after the two uses represents a practically proven measure of grease stability under permanent loading. The smaller the difference, the greater the load resistance of the grease sample.

Polyurea 2:
Two moles of 2,4- / 2,6-tolylene diisocyanate were added to a mixture of 1 mole of 1,6-hexamethylenediamine and 2 moles of stearylamine in ethyl acetate. After completion of the reaction, the solvent of the formed suspension is removed from the reaction under shear force exposure. The resulting finely divided polyurea 2 is dried under vacuum. The optical micrograph (FIG. 1) shows that the particle diameter is well below 100 μm. This is confirmed by particle size analysis by coherent light scattering. The weight average of the measurement is D [v, 0.5] = 30.79 μm.

  A 15% suspension of dry polyurea 2 in naphthenic base oil is stirred at 170 ° C. for 1 hour, then cooled and homogenized three times on a three-stage roll mill. Consistency is determined in comparison with a control grease of the same composition prepared “in situ”.

result:
Intrusion after use
P _u P _{w, 60} P _{w, 60,000}
Polyurea grease, 186 196 267
Reactor (invention)
Control grease, 196 200 298
“In situ” method

  Mixture of lithium soap oil and polyurea powder prepared according to the present invention.

  It was to determine whether mixing of the polyurea powder prepared according to the present invention would cause changes in the penetration and dropping point of commercial lithium soap greases. For this purpose, three different commercially available lithium soap greases were used and examined with and without the addition of polyurea powder. The lithium soap grease was heated to 170 ° C., temperature-controlled for 1 hour, and then passed through a roll mill three times for the case where polyurea powder was added and not added. The results were as follows.

  Experiments have surprisingly shown that a reduction in penetration, and thus an improvement in grease consistency, is achieved by mixing 2% polyurea grease with lithium soap grease. In addition, the dropping point is increased compared to pure lithium soap grease.

The optical micrograph (FIG. 1) shows that the particle diameter is well below 100 μm.

Claims (32)

  In a reactor, at least one isocyanate is reacted with at least one amine in at least one solvent, and the formed (poly) urea is dried in the reactor under shear force exposure to form a (poly) urea powder. A process for preparing (poly) urea powder, characterized in that it is formed.   The process according to claim 1, characterized in that the (poly) urea is selected from monourea compounds and polyurea compounds.   In a reactor, at least one polyisocyanate is reacted with at least one polyamine and optionally at least one monoamine in at least one solvent and the polyurea formed is subjected to shear force exposure in the reactor. The method for preparing polyurea powder according to claim 1, wherein the polyurea powder is dried to form a polyurea powder.   The process according to claim 3, characterized in that the weight ratio of the total weight of polyisocyanate and monoamine and polyamine to the total weight of solvent is from 10% to 50%.   Process according to one of claims 1 to 4, characterized in that the solvent is selected from organic solvents.   6. Solvent according to one of claims 1 to 5, characterized in that the solvent is selected from organic solvents selected from the group consisting of optionally substituted linear, branched or cycloaliphatic or aromatic hydrocarbons. The method described.   Polyisocyanates are 2,4′- and 4,4′-diisocyanatodiphenylmethane (MDI), hexamethylene-diisocyanate (HDI), toluene-diisocyanate (TDI), polymethylene polyphenylisocyanate (PMDI), naphthylene-diisocyanate 6. A process according to one of claims 3 to 5, selected from the group consisting of (NDI), dicyclohexyl-4,4'-diisocyanate and isophorone-diisocyanate (IPDI).   Monoamine and polyamine are ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine having a molecular weight of 250 to 10,000, 2 1,4-diaminotoluene and 2,6-diaminotoluene, bis- (4-amino-phenyl) -methane, polymethylene polyphenylamine, content of 1-8 mmol / g of primary or secondary amino groups and Polyethers containing amino groups having a molecular weight of 250 to 2,000, phenylenediamine, diethyltoluylenediamine, 2-methylpentamethylenediamine and butylamine, hexylamine, octylamine, stearylamine, olefin 8. One of claims 1 to 7 selected from the group consisting of ruamine, tridecylamine, coconut aliphatic amine, aniline, isopropylaniline, N, N-diethylaniline, p-toluidine, cyclohexylamine and dioctyldiphenylamine. the method of.   9. Process according to one of claims 1 to 8, characterized in that, in addition to monoamines and polyamines, further polyfunctional compounds which are reactive towards isocyanates are used.   The (poly) urea powder formed comprises a polyurea having a weight average molecular weight of 500 to 20,000 as determined by gel permeation chromatography against polystyrene as a standard of 200 to 2,000,000. The method according to one of claims 1 to 9.   11. Process according to one of claims 1 to 10, characterized in that the reaction of polyisocyanate with monoamine or polyamine is carried out at a temperature in the range of 20 to 120 [deg.] C.   The process according to one of claims 1 to 11, characterized in that the drying is carried out at a temperature in the range of 40C to 80C.   The process according to one of claims 1 to 12, characterized in that the drying is carried out under a pressure in the range of 100 to 300 mbar (0.01 to 0.03 MPa). 14. A process according to one of claims 1 to 13, characterized in that the shear force applied in the reactor is 1 to 10 < ⁴ > / sec.   15. A process according to one of claims 1 to 14, characterized in that the reactor is selected from a horizontal uniaxial mixer.   The process according to one of claims 1 to 15, characterized in that the (poly) urea powder obtained has an average particle size of less than 150 µm.   Process according to claims 1 to 16, characterized in that the (poly) urea powder obtained has an average particle size of less than 100 m.   The method according to claim 16 or 17, characterized in that the (poly) urea powder obtained has an average particle size of more than 20 μm.   19. A method according to claims 1 to 18, wherein more than 90% of the particles of the (poly) urea powder obtained have a particle size of less than 100 [mu] m.   (Poly) urea powder obtainable according to one of claims 1 to 19.   (Poly) urea powder having an average particle diameter of 20-100 μm.   22. (Poly) urea powder according to claim 20 or 21, having a content of volatile components such as solvents of less than 0.5% by weight. 15m having more than a specific surface area (measured by mercury porosimetry) ² / g, according to one of claims 20 22 (poly) urea powder.   20. A method for preparing a composition comprising suspending (poly) urea powder obtained according to one of claims 1 to 19 in at least one base oil.   25. The method of claim 24, wherein a suspension of (poly) urea powder in at least one base oil is treated with a high pressure homogenizer.   26. The method according to claim 25, characterized in that the base oil is selected from the group consisting of mineral oil and synthetic oil or natural oil.   27. A process according to claim 24, 25 or 26, wherein the amount of (poly) urea powder is from 2% to 25% by weight, based on the total weight of the base oil.   28. A method according to one of claims 24 to 27, wherein at least one further usual auxiliary substances and additives for lubricants are mixed.   29. A method according to one of claims 24 to 28, wherein at least one further thickener is mixed.   Use of (poly) urea powders obtained according to one of claims 1 to 19 as thickener.   Use of a (poly) urea powder obtained according to one of claims 1 to 19 in a lubricant.   30. Use of a composition obtained according to one of claims 24 to 29 as a lubricant, paint, lacquer, adhesive, paste, solution or the like.

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